Hub-and-Spoke Umbau: Multi-Tenant Zentrale + Satellite-Agent

- Backend: Customer/Satellite Models, customer_id auf Server/Job/Audit
- Satellite-API: heartbeat, poll (atomares Claiming), logs, result,
  scan-result, health-report - Auth via X-Api-Key (SHA-256 gehasht)
- Job-Queue: pending/claimed/running/success/failed + Stale-Janitor
- Batch-Trigger: ein Job pro Server, Satellite arbeitet sequenziell ab
- Credentials bleiben lokal: nur symbolische credential_ref zentral
- Neues Paket satellite/: Pull-Loop, WinRM/SSH/CAU/Scanner, PyInstaller-tauglich
- Frontend: Kunden-Switcher, Satelliten-View, Polling statt WebSocket
- Entfernt: WebSocket/Socket.io, Redis, zentrale Credentials, JobRunner
- Docs: README/AGENTS/PROMPT auf neue Architektur aktualisiert

backend/app/models/server.py

@@ -1,15 +1,19 @@
-"""Server inventory model."""
+"""Server inventory model.
+
+Credentials are NOT stored centrally. `credential_ref` is a symbolic name
+that the satellite resolves against its local credentials.yaml.
+"""
 
 import enum
 from datetime import UTC, datetime
 
-from sqlalchemy import DateTime, Enum, ForeignKey, String, Text
+from sqlalchemy import DateTime, Enum, ForeignKey, String, Text, UniqueConstraint
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
 from app.core.database import Base
 
 
-class ServerType(str, enum.Enum):
+class ServerType(enum.StrEnum):
     WINDOWS = "windows"  # WinRM
     LINUX = "linux"  # SSH
     CAU_CLUSTER = "cau_cluster"  # Cluster-Aware Updating
@@ -17,22 +21,33 @@ class ServerType(str, enum.Enum):
 
 class Server(Base):
     __tablename__ = "servers"
+    __table_args__ = (
+        UniqueConstraint("customer_id", "name", name="uq_server_customer_name"),
+    )
 
     id: Mapped[int] = mapped_column(primary_key=True)
-    name: Mapped[str] = mapped_column(String(255), unique=True, index=True)
+    customer_id: Mapped[int] = mapped_column(
+        ForeignKey("customers.id"), index=True
+    )
+    customer: Mapped["Customer"] = relationship(back_populates="servers")  # noqa: F821
+
+    name: Mapped[str] = mapped_column(String(255), index=True)
     hostname: Mapped[str] = mapped_column(String(255))
     port: Mapped[int] = mapped_column(default=5985)
     type: Mapped[ServerType] = mapped_column(Enum(ServerType), default=ServerType.WINDOWS)
     description: Mapped[str | None] = mapped_column(Text, nullable=True)
     tags: Mapped[str | None] = mapped_column(String(500), nullable=True)  # comma-separated
 
-    credential_id: Mapped[int | None] = mapped_column(
-        ForeignKey("credentials.id"), nullable=True
-    )
-    credential: Mapped["Credential | None"] = relationship(lazy="selectin")  # noqa: F821
+    # Symbolic reference to a credential stored locally on the satellite
+    credential_ref: Mapped[str | None] = mapped_column(String(255), nullable=True)
 
+    # Last health result reported by a satellite
     last_health_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
     last_health_ok: Mapped[bool | None] = mapped_column(nullable=True)
+    last_health_message: Mapped[str | None] = mapped_column(Text, nullable=True)
+
+    # Set by network scan jobs
+    discovered_by_scan: Mapped[bool] = mapped_column(default=False)
 
     created_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), default=lambda: datetime.now(UTC)
@@ -44,5 +59,5 @@ class Server(Base):
     )
 
     jobs: Mapped[list["UpdateJob"]] = relationship(  # noqa: F821
-        back_populates="server", cascade="all, delete-orphan"
+        back_populates="server"
     )